gene therapy using stem cells technology

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1. BioEd Online
Hot Topics in Biology
Embryonic Stem Cells
by Joseph Marx, PhD
Compiled and Edited by
Nancy Moreno, PhD, and
Deanne Erdmann, MS
NIH

2. www.BioEdOnline.org
BioEd Online
What is a Stem Cell?

Unspecialized cells

Able to self-renew without
differentiating for extended
periods of time

Ability to differentiate into
specialized cells

Embryonic and adult stem cells
are derived from different sources.
TIME 2001
Human blastocyst
showing inner
cell mass and
trophectoderm
Photo: Mr. J. Conaghan

3. www.BioEdOnline.org
BioEd Online
What is an Embryonic Stem Cell?
Fusion
of nuclei
First cell
division
Only cells between the nuclei
fusion and blastocyst stages are
considered true stem cells.
Blastocyst (~5-6 days old):
a “pre-embryo” ball of cells which
has not implanted in the uterus.
Stem cells are harvested
from the inner cell mass.
By the latter stages
of development in the
fetus, cells already have
“decided” which
tissues they are
to become.
Placenta cell
Stem cell

4. www.BioEdOnline.org
BioEd Online
Embryonic Stem Cells are Derived from Blastocysts
Fusion
of nuclei
First cell
division
Blastocyst
(~5-6 days old)
Stem cells are harvested
from the inner cell mass.
Undifferentiated
stem cells are
cultured (grown)
in the laboratory.
Placenta cell
Stem cell

5. www.BioEdOnline.org
BioEd Online
Embryonic Stem Cells Can Become Any
Tissue in the Body
Blastocyst
Cultured laboratory
stem cells
Scientific manipulations entice stem cells to become
specialized tissues (blood, muscle, neuron, etc.).
Blood cells
Muscle cells
Neuron (brain) cells
Placenta cell
Stem cell

6. www.BioEdOnline.org
BioEd Online
The Official National Institutes of Health
Resource for Stem Cell Research
Stem Cells: Scientific Progress and
Future Research Directions reviews
the state of the science of stem cell
research as of June 17, 2001. This
report includes subject matter
addressing stem cells from adult,
fetal tissue, and embryonic
sources. It is available at:
http://stemcells.nih.gov/info/scireport/.